1. Technical Field
The present disclosure relates generally to a method for evaluating gear wear on chain conveyors and particularly to evaluating gear wear on chain conveyors in the pulp and paper industry and the recycling industry.
2. Related Art
In the pulp and paper industry and the recycling industry, equipment manufacturers periodically evaluate the condition and performance of the equipment sold to customers. In pulp and paper wood yards, for example, manufacturers preliminary inspect a wood yard several months before an annually scheduled maintenance shutdown. These intermediate, preliminary inspections allow the equipment manufactures to provide the wood yard operators with data and allow the mill yard operators to plan for equipment repair, replacement, or refurbishment during a later scheduled maintenance shutdown.
Wood yards generally have different types of chain conveyors, which may be used to transfer logs, wood chips, or other products throughout the wood yard. These may include for example, wide wood chain conveyors, incline chain conveyors, chip infeed chain conveyors, drain discharge chain conveyors, and power feed chain conveyors. Each chain conveyor may have at least two distally disposed shafts and a sprocket on each of the shaft engaging links in a chain. Sprocket teeth primarily wear on the tooth face that pulls against the chain link; however, all tooth faces that pull against the chain link tend to wear evenly on a given sprocket, thereby rendering visual inspection unreliable. The sprocket is also set into the chain conveyor equipment, and the exposed sprocket teeth are usually obstructed by chain links engaging the sprocket tooth. For at least these reasons, operators have difficulty accessing a sprocket tooth to evaluate sprocket tooth wear without first deactivating and partially dismantling the chain conveyor. However, removing a sprocket from a chain conveyor requires an extended shutdown, which contributes to loss of production.
By way of example, an inspecting equipment manufacturer may recommend that the extracted sprocket be sent to an offsite facility for precision measurement of tooth wear. Precision measuring equipment, such as the devices disclosed in U.S. Pat. Nos. 3,100,940; 3,193,936; 4,137,642; 5,392,644; and 5,461,797 tends to be bulky, requires precise calibration before use, and necessitates having the entire sprocket at the same location as the precision measuring equipment. The precision measuring equipment's size and sensitivity generally preclude the prevision measuring equipment's portability. However, shipping worn sprockets back to the manufacturer for detailed wear analysis can delay production significantly. Furthermore, the sprockets themselves can be quite heavy and removing and shipping the sprockets poses safety risks to handling personnel.
Moreover, wood yard operators generally do not a have clear understanding of the condition of their sprockets. Therefore, maintenance tends not to be done at time of convenience, but rather at the time of emergency.
When a sprocket fails, the broken sprocket tooth renders the chain conveyor non-functional, which can pose an immediate safety risk to operating personnel and disrupt production for weeks. Accordingly, there is a long felt need for a device and method that overcomes the limitations of the prior art.